A Semi-simple Steam Box

I’m making some chairs from an oak tree that was taken down in our back yard. These chairs require that some of the parts be steam bent. I’m starting with the simplest of the few chairs that I think I’ll be able to get out of this log, a post and rung rocker. The two long back posts need a gentle bend in the design I’m building. So I needed a steam box. I could have gone the simplest route and bought a PVC pipe and some end caps. That’s not my style though. I like wood.

The materials for the steam box are pretty simple and available at any home center. There are two six foot 1 x 4s and to six foot 1 x 6s. Plus some nails (mine are cut finish nails), a few plumbing parts and some hinges (I ended up using different hinges).
The parts to be steamed are supportd above the bottom of the box by some dowels so that the steam can circulate around them. These dowels were spaced about 6″ apart and placed about 1″ above the bottom of the box. Apparently either my 3/4″ auger is oversized (not likely) or this dowel was quite undersized (pretty typical of home center dowels).
The box is just nailed together. There is no joinery at all as there’s really no need. I used cut finish nails. The end cap is rabbeted on all four sides to provide some resistance to racking.
The end cap is, again, just nailed on with cut finish nails.
Time to provide an entrance for the steam. I bored a hole about 1-1/4″ or 1-1/2″ (don’t remember which it was) in diameter. This hole is centered on the bottom of the box.
Ovder the hole, I screwed a floor flange for iron pipe. This one is either a 3/4″ or 1″ floor flange, I don’t remember the exact size. Bigger is better as you want to fill the box with as much steam as possible. I used brass PEX connectors to attach the supply hose to the box.
I used brass PEX connectors to attach the supply hose to the box and kettle. The hose is standard heater hose, available in most home centers or auto part stores. It’s designed for high temp applications. The hose is just attached to the PEX connectors with hose clamps so it can be easily disassembled.
The door on the opposite end is made identically to the end cap. The only difference, obviously, is that it’s attached with hinges. I had to buy these hinges and bend them as the other ones I had didn’t work out. I also picked up a cheap pine knob. Looks nicer than the shiny handle in the first pic.
Time to add some legs to get the box up above the kettle. I had my apprentice cut the leg stock. Look at that perfect grip on the saw and the proper stance and alignment! She makes a dad so proud :). She cut right to the line too.
We screwed the legs that she cut to a 2 x 2 block of poplar and then attached them to the bottom of the box with the hinges from the first picture so that they could be folded up for storage. The front set of legs (closer to the door) is also 1″ shorter than the rear set so that the condensate inside the box will drain out rather than pool up inside the box.
The tea kettle is just an old one that we had laying around. The PEX connector was driven into the spout with a mallet and the hose attached with a hose clamp. The electric burner is a $20 version from the big box store. The kettle will steam this box for at least 2 hours on a single fill of water. There was still plenty of water left when I was done, so I’m not sure how long it will actually go for.
It works! These legs are shaved to about 1-1/2″ in diameter and they bent without any problem. Well, it took some muscle, but the ratchet straps pulled everything smoothly and the wood bent without any cracking. Granted this is a gentle bend, but it’s a good start.

So the next trial of the steam box will be some back bows and arm rails for a sack back Windsor chair (or two). While the stock for those parts is only on the order of 3/4″ thick or so, the bends are much more dramatic, so they’ll be a much better test of the steam box and the wood from this tree. I’m excited though. This is fun stuff!

More Riving, Almost Done

I did a bit more riving last Sunday and almost have the first 5′ log all split up into usable sections. Being a backyard tree, I did get quite a bit of waste splits as well as good splits. No big deal. The waste splits still make good firewood once they season.

Forest trees tend to grow straighter and have fewer lower limbs (a.k.a. knots). So if you are able to get your hands on a good forest tree, you will likely get more straight splitting usable lumber out of it (see most of the trees that Peter Follansbee uses) vs. a backyard tree. Still, some suburban and urban trees will yield to the wedge and froe. You might get lumber with a bit more twist and it may not split perfectly straight, but by riving a bit more oversized than you would with a perfect forest tree, you can still get a an awful lot of usable wood from the right backyard tree. And in many cases, you can get this lumber for free if you look around. Talk to your local tree services and I’ll bet you can find some.

Start with a fairly straight log. You can often read the bark to judge how straight the tree will split (though this is not always reliable).
Using a pair of steel wedges and a wooden glut or two, split the log in half. This is typically the hardest split. They get easier as they get smaller.
Split each log half equally in half again to yield quarters.
Then split the quarters into eights. You can stop here or split into sixteenths if you have a particularly large log. Usually eighths is enough. Always try to split the piece in half for the best chance of getting a good split.
Eighths split into project parts. The left pile has enough posts, rungs and slats to make three post & rung chiars. The right pile has parts for bows, arm rails and spindles for two sack back Windsor chairs. I still have two eighths left to split, possibly for rockers for the post and rung chairs, or maybe a carved box or two, depending on how well they split.

Who Splits Logs when it’s 90° Outside?

Um, yeah, me. There’s a reason that smart people like Peter Follansbee, Curtis Buchanan and Mike Dunbar do this stuff when there’s still a bit of snow on the ground. I went through three t-shirts, two bandanas, a gallon of ice water, two IPAs and four ibuprofen (hey Bob, how many Snickers bars would this be?), but I got this 5 foot red oak log split into eighths on Saturday before the skies opened up. This log is destined to become at least one, but hopefully several chairs.

I still have another five footer to go if anyone wants to come over and swing a sledge hammer for a few hours…anyone…anyone? At least the second one will be cut into shorter sections first. That one will be used for joint stool stock for a couple of reproductions we are going to work on in the joiner’s shop at Pennsbury Manor. If you can’t make it to NJ this week, you can come to Pennsbury on August 4th from 1-4 PM and help me split one there. Maybe it won’t be in the 90s by then :).

logs2 logs1